May 19 (Bloomberg) -- John McCain threatens to ban toy imports from China and lashes its government for stifling religion and free speech. Barack Obama and Hillary Clinton want to punish China for currency manipulation.

The presidential candidates' rhetoric in recent weeks signals that a tougher U.S. policy toward China may be in store under a new administration. History suggests otherwise.

Presidents Bill Clinton and George W. Bush denounced China on the campaign trail and promised a harder line. Both changed course when confronting the realities of governing, which today include China's role as the second-largest foreign owner of U.S. debt -- its holdings have increased eight-fold since 2000 -- and as a central partner in efforts to contain North Korean nuclear ambitions.

``There is a tendency for president after president to come in bashing,'' says Richard Baum, a China scholar at the University of California at Los Angeles who says he quit as an informal Clinton adviser last month after she began attacking the Asian nation. ``But six months later, everything is the same, because the relationship is too important.''

That sums up the experiences of the last two presidents. Bill Clinton campaigned in 1992 against coddling the ``butchers of Beijing'' who ordered the crackdown on protesters in Tiananmen Square. Bush in 2000 said he would recast U.S. policy to treat China as a ``strategic competitor,'' not a partner.

Once in Office

In office, Clinton backed legislation normalizing trade relations, visited China and even took part in a welcoming ceremony near the site of the 1989 bloodshed. Bush, after the Sept. 11 attacks, sought Chinese support for fighting terrorism.

``Once a president is elected, he or she has a year to unwind all the anti-China rhetoric they used in the campaign,'' said Charles Freeman, a fellow at the Washington-based Center for Strategic and International Studies and a former top U.S. trade official on China.

China's role has grown so large that the new president may come under pressure even sooner to ensure smooth relations.

Last year, China surpassed Canada to become the largest exporter to the U.S., selling $322 billion in goods; that's more than triple the amount in 2000, before Bush took office. American exports to China have risen more than 400 percent since 2000, according to U.S. Commerce Department figures.

One-third of the U.S.'s almost $100 billion in textile and apparel imports were from China last year, as were eight in 10 toy imports.

Financing the Deficit

China is also helping finance the U.S. budget deficit, holding $491 billion in Treasury securities as of the end of March, second only to Japan. That compares with $60 billion at the end of 2000.

Diplomatically, it has played a role in negotiations aimed at persuading North Korea to give up its nuclear weapons program. The U.S. has also sought Chinese support for stronger sanctions on Iran in the United Nations Security Council.

The China issue didn't loom large on the 2008 campaign trail until the April 22 Pennsylvania primary. That's when the United Steelworkers union and steel manufacturers worked to focus attention on trade complaints against China -- and Democratic contenders Obama and Clinton responded.

Clinton, 60, a New York senator, says that as president she would formally label China a currency manipulator because it has kept the yuan artificially low in value against the dollar, making its exports to the U.S. cheaper. ``I will get tough on China,'' she said on April 16.

Dumping Allegations

Obama, 46, accuses China of tilting the playing field by dumping products in the U.S., violating intellectual-property rights and ``grossly undervaluing'' its currency.

``We need to finally confront the issue of trade with China,'' the Illinois senator said on April 14. ``Trade with China will only be good for you if China itself plays by the rules.''

While all three candidates have taken a break from their criticisms of China to issue statements of sympathy for victims of last week's earthquake, the respite isn't likely to last.

Both Democratic candidates have endorsed legislation that would make it easier for U.S. companies to seek higher import duties on Chinese products in compensation for its undervalued currency. They also call for greater scrutiny of sovereign- wealth funds, pools of government-controlled money that invest in companies. The $200 billion China Investment Corp. last year bought stakes in Morgan Stanley and Blackstone Group LP.

And they question whether Bush should attend the opening ceremony of the Beijing Olympics in August in light of China's human-rights violations in Tibet and support for a Sudanese government accused of committing genocide in Darfur.

`Winds Have Shifted'

Proponents of a tougher U.S. policy on trade with China say Obama and Clinton will have to follow through if elected since they have taken such specific positions. ``We're not naive, but the winds have shifted,'' says Bob Baugh, executive director of the industrial union council at the AFL-CIO, the largest U.S. labor organization.

McCain, 71, the presumptive Republican nominee, seized on the issue of unsafe toy imports after a recall of Chinese-made products.

``If I were president of the United States, the next toy that came into this country from China that endangered the lives of our children, it would be the last,'' he said on April 22.

During the past year, McCain has taken Chinese leaders to task for denying their citizens freedom of worship and speech, supporting ``pariah states'' such as Myanmar and Sudan and promoting regional organizations that seek to exclude the U.S. from Asia.

Only for Democracies

The Arizona senator has proposed reconfiguring the Group of Eight industrialized nations to keep China from joining, even though its economy is bigger than all but three current members. He says the G-8 should be limited to democracies.

Randy Scheunemann, McCain's chief foreign policy adviser, says the senator will govern no differently than he has campaigned regarding China: ``He does not advocate any positions or principles today that are different from what he intends to carry out if he should become president.''

Clinton's policy director, Neera Tanden, says the candidate is determined to reduce the ``unprecedented'' trade deficit with China as well as U.S. indebtedness to that nation.

``Senator Clinton believes this situation is not sustainable,'' Tanden says. ``She is serious about fixing it. She will enforce trade laws on the books, take a hard line against currency manipulation that puts U.S. exporters at a disadvantage, and make fiscal responsibility a top priority.''

China's ambassador to the U.S., Zhou Wenzhong, shrugs off criticisms from the presidential candidates. ``My friends advise us not to take this campaign rhetoric too seriously,'' he said May 14 at the U.S. Chamber of Commerce in Washington. ``The most important thing is the policies.''

Under Strain

Yan Xuetong, director of the Institute of International Studies at Tsinghua University in Beijing, says Chinese-U.S. relations might be more stable under a McCain presidency than with either Democrat. Either way, he says, the relationship will be under strain.

``No matter who wins the election, China will have a tougher period in the early part of the presidency and then the relationship will improve,'' Yan says.

Still, Stephen Roach, chairman of Morgan Stanley's Asia division in Hong Kong, says the next president may have more difficulty retreating from anti-China statements, given how strongly such rhetoric resonates among voters.

In an interview with Bloomberg Radio, Roach asked: ``Can a president who gets elected running on this theme just all of a sudden get sworn in on Jan. 20, 2009, and say, `Oops, I didn't mean it'?''

To contact the reporter on this story: Ken Fireman in Washington at kfireman1@bloomberg.net; Mark Drajem in Washington at mdrajem@bloomberg.net

Last Updated: May 19, 2008 14:20 EDT